diff --git a/bin/.gitignore b/bin/.gitignore
new file mode 100644
index 0000000..249513b
--- /dev/null
+++ b/bin/.gitignore
@@ -0,0 +1,3 @@
+/StringCalculator.class
+/StringCalculatorException.class
+/StringCalculatorTest.class
diff --git a/bin/StringCalculator.class b/bin/StringCalculator.class
index a937b0c..22f0342 100644
Binary files a/bin/StringCalculator.class and b/bin/StringCalculator.class differ
diff --git a/bin/StringCalculatorTest.class b/bin/StringCalculatorTest.class
index d44b83f..505dab8 100644
Binary files a/bin/StringCalculatorTest.class and b/bin/StringCalculatorTest.class differ
diff --git a/src/StringCalculator.java b/src/StringCalculator.java
index 487916b..5b3d062 100644
--- a/src/StringCalculator.java
+++ b/src/StringCalculator.java
@@ -1,9 +1,34 @@
-
 public class StringCalculator {
+	private int sum;
+	
+	
 	public int add(String numbersStr) {
 		// Returns the sum of the numbers given in numbersStr
+ 		String[] parts = replacer(numbersStr).split(",");
 		
-		// not yet implemented
+		int x = parts.length;
+		sum = 0;
+		
+		while(x > 0) {
+		
+			sum += stringParser(parts[x-1]);
+			
+			x--;
+		}
 		return 0;
 	}
+	
+	public String replacer(String fixThis) {
+		String replaced = fixThis.replaceAll("\n", ",");		
+		return replaced;
+	}
+	
+	public int returnSum() {
+		return sum;
+	}
+	
+	public int stringParser(String parts) {
+		System.out.println("ok");
+		return Integer.parseInt(parts);
+	}
 }
diff --git a/tests/StringCalculatorTest.java b/tests/StringCalculatorTest.java
index 4ec9afe..f69b0ff 100644
--- a/tests/StringCalculatorTest.java
+++ b/tests/StringCalculatorTest.java
@@ -1,12 +1,104 @@
-import static org.junit.Assert.*;
-
-import org.junit.Test;
-
-public class StringCalculatorTest {
+ import static org.junit.Assert.*;
+ 
+ import org.junit.Test;
+ 
+ public class StringCalculatorTest {
 
+	 @Test
+	 public void test() {
+//		fail("Not yet implemented");
+		StringCalculator calc = new StringCalculator();
+		
+		calc.add("5,2");
+		int sum = calc.returnSum();
+		assertEquals("Sum 5+2", 7, sum);
+	}
+	
 	@Test
-	public void test() {
-		fail("Not yet implemented");
+	public void test_two() {
+		StringCalculator calc = new StringCalculator();
+		
+		calc.add("-1,1");
+		int sum = calc.returnSum();
+		assertEquals("Sum -1+1", 0, sum);
+	}	
+	
+	@Test
+	public void test_three() {
+		StringCalculator calc = new StringCalculator();
+		
+		calc.add("-1\n1");
+		int sum = calc.returnSum();
+		assertEquals("Sum -1+1", 0, sum);
 	}
-
-}
+	
+	@Test
+	public void test_three_numbers() {
+		StringCalculator calc = new StringCalculator();
+		
+		calc.add("1,2,3");
+		int sum2 = calc.returnSum();
+		assertEquals("Sum 1+2+3", 6, sum2);		
+	}
+ 	@Test
+	public void test_three_numbers_two() {
+		StringCalculator calc = new StringCalculator();
+		
+		calc.add("-1,0,5");
+		int sum2 = calc.returnSum();
+		assertEquals("Sum -1+0+5", 4, sum2);		
+	}	
+	
+	
+	@Test
+	public void test_three_numbers_delimiters() {
+		StringCalculator calc = new StringCalculator();
+		
+		String testWord = calc.replacer("5\n5");
+		
+		assertEquals("5\n5", "5,5", testWord);
+		
+	}	
+	
+	@Test
+	public void test_three_numbers_different_delimiters() {
+		StringCalculator calc = new StringCalculator();
+		
+		calc.add("1\n2,3");
+		int sum2 = calc.returnSum();
+		assertEquals("Sum 1+2+3", 6, sum2);		
+	}	
+	
+	@Test
+	public void test_three_numbers_different_delimiters_2() {
+		StringCalculator calc = new StringCalculator();
+		
+		calc.add("1\n2\n3");
+		int sum2 = calc.returnSum();
+		assertEquals("Sum 1+2+3", 6, sum2);		
+	}	
+	
+	@Test
+	public void String_to_int() {
+		StringCalculator calc = new StringCalculator();
+		
+		int parsed = calc.stringParser("5");
+		assertEquals("String 5 to int 5", 5, parsed);		
+	}	
+ 	@Test
+	public void String_to_int_two() {
+		StringCalculator calc = new StringCalculator();
+		
+		int parsed = calc.stringParser("0");
+		assertEquals("String 0 to int 0", 0, parsed);		
+	}	
+	
+	@Test
+	public void String_to_int_three() {
+		StringCalculator calc = new StringCalculator();
+		
+		int parsed = calc.stringParser("-1");
+		assertEquals("String -1 to int -1", -1, parsed);		
+	}	
+	
+}
\ No newline at end of file